I coach two senior executives who do more or less the same job in two different companies. They have about the same number of direct reports, they manage P&Ls that are roughly the same size and complexity, and they report to fairly similar bosses. Both are women.

One of these execs is run ragged all the time. She barely has time to sleep, and her family doesn’t see nearly enough of her. She works every weekend, and late at night after her kids and husband have gone to bed. She has confided in me that her health is suffering and she feels highly stressed most of the time.

The other works hard but has a relatively balanced life: she takes vacations, spends many weekends with her family, and is generally home by 7 or so, except when she’s traveling. She has time to work out. Her job is stressful, but—for the most part—she’s happy and energized.

Why are their lives—and their experience of work—so very disparate? I’ve observed two critical differences: The second executive has a strong team and fully delegates to them. The first has a less capable team, and she doesn’t delegate very much at all. I’ve come to the conclusion that having great people, and delegating to them, are the two most important secrets of those executives you envy—the ones who don’t seem to be overwhelmed and struggling.

Now, if you’re a leader, and you don’t delegate enough, I’m pretty sure I know the reasons why—we’ve been hearing them from managers for years: You’re worried your folks won’t do things as well or as quickly as you. You like doing some of the things they probably should be doing, and you don’t want to give those things up. You’re worried that you’ll be seen as less valuable if others are doing part of the important work. You’re not sure the people who work for you are capable of more than they’re doing now. Let’s blow these excuses up, one by one:

They won’t do things as well or as quickly as you do. You’re right, they won’t—at least not initially. But if they’re capable, and you delegate skillfully, eventually they will—and you’ll be freed up to do all the things you’re not now doing—like thinking about how to improve your department, let alone sleeping or spending time with your kids. If you continue to do work that should be done by others because you’re the only one who can “do it right”—you’ll become a terrible bottleneck, and your group will become less and less productive. Plus, you’ll be working 24-7. Nobody wins.

You don’t want to give some things up. This is really common; you’re great at some things, and you derive satisfaction from doing them. Continuing to do tasks that are in your comfort zone, rather than delegating them to others, can even feel like a security blanket—a kind of stress reducer. Unfortunately, it’s a short-term palliative that has long-term negative consequences. Years ago, I coached a CEO who had been the head of sales before his promotion. He continued to spend quite a bit of time going over detailed sales reports with the analysts who worked for his new head of sales—simply because he felt comfortable and reassured doing that. It was frustrating for his Sales SVP, confusing to the analysts, and meant that he didn’t have time for important CEO-level work like meeting with key business partners. Getting a bigger job doesn’t mean you get to do whatever you like: it means you need to do what the job requires and let other people do their jobs.

You’re worried you’ll be seen as less valuable. That’s only true if you don’t take advantage of the time you’ll get back to do the higher order work that hasn’t been getting done. For instance, as in my previous examples, thinking about how to improve your department, or creating stronger peer and senior level relationships. You might even create the time you need to identify and then offer to do new, more strategic work that no one is seeing. A client of mine, a senior marketing leader and very good delegator, recently realized that his company didn’t have a clear employee brand, and that it was hurting them in the job market. He outlined to the CEO why this was important and how it could be addressed—and was given a raise and tasked with overseeing the effort. Delegating well can be the fastest route to a promotion, if that’s what you want.

You’re not sure your people are capable of doing more. This takes us back to the first “secret”: have great people. If you’re not delegating because you don’t think the people who work for you are capable of doing higher-order work…then you’ve got the wrong people working for you. Try this: for a moment, think about the job of the most senior person who reports to you (vs. the person who now has that job). Think of things that you’re doing that ought to be a part of that job. Now think about the actual person in that job; if there are major gaps between what that person could actually take off your plate, and what someone in that job ought to be capable of doing—then you’ve under-hired for that job. I know a lot of very smart and skilled managers who “fill in” for their people in this way. It’s bad for them (leads to burnout), it’s bad for their people (they get an inflated and inaccurate sense of how good they are), and it’s bad for the organization (the manager is less available to do the work he or she should be doing).

Here are two final suggestions to help you delegate more, and more effectively. First, whenever you’re wondering whether or not you should delegate a responsibility, remind yourself that, as a leader, you should only do what only you can do. In other words, you shouldn’t be doing things that other people could and should be able to do. Second, for more practical help in delegating well, you can find detailed “how-tos” here.

And if, a year from now, you’re on vacation and celebrating your new promotion, all because you’ve strengthened your team and delegated to them—please send me a postcard!